The present invention concerns a stacked-plate heat exchanger. Several corrugated and essentially rectangular plates are stacked and welded together to be sealed off from the environment. There are hollow spaces between the plates, and intake-and-outlet openings at the corners. Alternating spaces are occupied by one of two fluids. The fluids exchange heat.
Welded-stack heat exchangers are better than those that can be disassembled because the latter require resilient seals between the plates formed of, for example, an elastomeric material. Such seals can leak when they break down due to the presence of corrosive fluids or exposure to high temperatures and pressure, for example, and then they must be replaced. Welded-stack exchangers can be operated at higher temperatures and pressures and with more corrosive fluids because they have no elastomeric seals.
One type of welded-stack heat exchanger is known from GB Patent Application Nos. 2 126 703 and 2 167 175. The edges of adjacent plates are welded to strips of metal. The strips act as both spacers and seals. Each strip is welded to one plate such as to admit one particular fluid and the adjacent plate is positioned and welded to the same strip. The latter weld must always be welded through the upper plate. To prevent damage to the previous weld, each strip must be offset from the strip in the previous fluid space.
This requirement makes such an exchanger expensive to manufacture.